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Question about viruses (particularly hiv)

About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.

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Postby biohazard » Fri Apr 20, 2012 10:02 am

All viruses can cause a "disease" in some way. They are parasites and thus by definition harmful to their hosts in some way. However, in order to cause a human disease the virus must be able to bind its target molecule on a human cell, enter the cell and produce copies of itself. Finally, it must be able to escape the cell and infect others. If any one of those steps fails, there will be no disease. Failure can be the result of wrong specificity (the virus infects completely different cell types or species), immune defense, viral inactivation due to other external sources and so on.

Also, many human viruses are so specialized to infect humans that they cause mild and subclinical infections that normally go unnoticed - there is no real use for most viruses to cause a wide-spread immune activation, and/or a fulminant disease that kills their host.

Actually many of the most dangerous viral diseases are caused by viruses that do not normally infect humans, but by chance happen to do so. The wildly activating human immune response is then often the biggest culprit for the severe symptoms, the virus itself not so much.
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Re: Question about viruses (particularly hiv)

Postby JorgeLobo » Fri Apr 20, 2012 10:20 am

An infective viral particle population without a coincident host or cell for replication is not per se "dormant." Viral dormancy (or latency) is more commonly used to describe the presence of viral infectivity in a host without causng an obvious disease. Example would be herpes zoster remaining in he host in absence of apparent diease after chickenpox establishing shnigles decades later. Folks have also referred to initial HIV infection of lymphocytes by such terms.

I'm not aware of a term of art for an infective virus in absence of a host. ATCC sells for example VR-96 influenza "virus" frozen.
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